1. Field of the Invention
The present invention generally relates to a method of classifying a dent on a surface of a shipping container as being in an acceptable or unacceptable classification and also to a method of preventing formation of the dents. The present invention further relates to a method of measuring a depth of the dent and a measurement apparatus for measuring the depth of the dent.
2. Description of the Related Art
In industry, goods, such as chemicals, are shipped in shipping containers. Recipients of the shipping containers are increasingly concerned about the number and size of dents in such shipping containers. In particular, relatively large dents damage the shipping container which can lead to contamination of the contents of the shipping container. The relatively large dents create cracks in the shipping container and the contents of the shipping container typically react with the material of the shipping container about the cracks such that the contents become contaminated. Shipping containers can include a lining and relatively large dents crack the lining which results in contamination of the contents. Further, some shipping containers include a plunger inside the shipping container used to remove the contents from the shipping container. Dents of a sufficient depth prevent the plunger from operating properly. Currently, no adequate method exists for identifying contaminated contents without opening the shipping container to examine the inside of the shipping container.
Recipients of the shipping containers inspect the shipping containers for dents and reject shipping containers having relatively large dents. Current inspection of the shipping containers is subjective. In other words, the inspection does not involve quantifying the depth of dents for an objective inspection. Typically, the recipient has a photograph depicting a dent of an unacceptable classification, i.e., a dent that is relatively large such that the contents are contaminated. The recipient visually compares the dent on the shipping container with the photograph and the shipping container is rejected if the dent on the shipping container visually appears to be deeper than the dent depicted in the photograph. This subjective analysis is not consistent, i.e., is not accurate and repeatable, and leads to shipping containers being rejected even though the dent is not in the unacceptable classification. Alternatively, recipients of the shipping container open the shipping container to inspect the contents of the shipping container for contamination. Such an inspection is time consuming and often the contents of the shipping containers degrade upon the opening of the shipping containers.
In addition, shippers of the shipping containers seek to identify the source of the dents so that the source may be eliminated. However, an objective method of identifying and eliminating the sources of dents has not been identified in the prior art. Without an objective method, much time and effort is consumed investigating the source of the dents and often resources for such time and effort is not available.
Measurement apparatuses are generally known for quantifying contours of a surface. Such measurement apparatuses generally include a frame, a mounting device fixed to the frame for mounting the measurement apparatus to the surface, and a measuring device fixed to the frame for measuring the contour of the surface. However, the surface of the shipping container defines features, e.g., ribs, and the surface of the shipping container may have several dents. The measurement apparatuses of the prior art are not conducive to measuring dents on the surface of shipping containers because the measurement apparatus is not easily mounted to such surfaces. Specifically, the measuring device must be aligned with the dent such that the mounting device is positioned flush against the surface in order to achieve an accurate measurement. However, the features and the several dents in the surface often prevent the mounting device from being positioned flush against the surface.
Accordingly, it would be desirable to establish methods of measuring, classifying, and preventing dents on the surface of the shipping container. It would also be desirable to manufacture a measurement apparatus that is conducive to measuring the depth of the dent in the surface of the shipping container.